Selector-switch.



A. H. ADAMS & A. E. LUNDELL.

SELECTOR SWITCH. APPLICATION FILED JAN. 31. 1916.

1,233,831 Patented July 17, 1%?:

2 SHEETS-SHEET 1.

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SELECTOR SWITCH.

APPLlCATiON FILED JAN a1. 1915.

1,233,831, Patented July 1?, 191?.

2 SHEETSSHEET 2.

UNITED STATES PATENT OFFICE.

ARTHUR H. ADAMS, OF SPARKILL, AND ALBEN E. LUNDELL, OF NEW YORK, N. Y., ASSIGNORS TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y.,

A CORPORATION OF NEW YORK.

SELECTOR-SWITCH.

Specification of Letters Patent.

Patented July 17, 1917.

Application filed January 31, 1916. Serial No. 75,369.

an idle outgoing line upon the initiation of a call.

The principal object of this invention is the provision of switching mechanism and operating circuits therefor in which the 1 number of controlling magnets is reduced to a minimum.

In the present disclosure the invention is shown in connection with a line switch, that is one of the switches therein disclosed, and the controlling circuits therefor are provided for each subscribers line. Leading from said switch, are a plurality of trunk circuits, in the present instance ten in number, which extend to the first selector switches. It is of course obvious that the present invention may be employed in a call distributing system to select trunks extending to a manual operators position.

Figure l of the drawing is an edge view of one of the switching devices employed with the present invention.

Fig. 2 is a side elevation of the same with parts broken away.

Fig. 3 is a cross section on the line 3-3 of Fig. 2.

Fig. 4. diagrammatically illustrates the switch, a subscribers line and the operating circuits by means of which said switch extends said line to an idle trunk line.

We will first describe the mechanical structure of the switch. The supporting members 1 and 2 may be angle irons as illustrated in Fig. 2. Secured tothese angle irons, adjacent to each other and substantially parallel to each other, will be a plu members 1 and 2. The rods or wires 1 are the multiple terminal contacts for the outgoing or trunk lines. These terminal rods are common to the whole group of 100 switches. The manner of mounting these rods will be hereinafter described.

Each switching mechanism 8 includes a pair of parallel side plates 5 and 6, which are connected near their opposite ends by the webs 7 and 8 respectively. The web 7 is offset and is secured to the supporting member 1 by means of a screw 9, or in any desired manner. The opposite ends of the members 5 and 6 are provided with hooklike extremities 10, which are arranged to clampingly engage the lower edge of the member 2. The members 5 and 6 are also each provided with a lug 11, arranged to be positioned in the openings 12 in the bar 2. The plates 5 and 6, which are in reality a channel member with the web portion cut away, intermediate the ends, form the supporting structure for the movable portion of the switch.

Secured in any desired manner to the plates 1 and 2 between the members 5 and 6, are the ends of an arcuate supporting member 15. Secured to the supporting member 15 by and 22. These cup-shaped members are provided with outwardly extending flanges 24 and 23 respectively, between which is clamped the disk 25 of insulating material by means of screws 26. The flange 24 of the cup-shaped member 21, is offset and extended outwardly to form the ratchet wheel 27 by means of which the switch brushes are rotated. V

.Secured to the insulating disk 25 near the circumference thereof, area plurality of conducting segments 28, to each of whifli is secured a brush 29. In the present embodiment of the invention these segments 28 are of equal length and live in number. The

ends of adjacent segments are separated by a distance less than the distance between adjacent rods 4. Associated with each of said segments 28 is a brush 29 which may be made integral therewith by a stamping process, which is readily understood. Secured to the enlarged portion 18 of the supporting member 6 by being clamped between y it and the ring 31, is an annular insulating I drawing.

The web 8 at the lower end of the members 5 and 6,is offset outwardly and the pole piece 35 of the stepping magnet 36 is secured thereto. The opposite end of the pole piece extends beyond the spool-of the magnet 36 and is turned at an angle as is clearly shown in-Fig. 2. Pivotally supported between the members 5 and 6 is the armature 37 of the magnet v36. Secured to the armature 37 in any desired manner, is the extension 38 to the end of which is secured the metallic block 39 which is arranged to engage successive ratchet teeth on the wheel 27 upon repeated energizations of the ma net 36 and thus cause the rotation of the sai ratchet wheel and the disk 25 carried thereby. Retrograde movement of the ratchet wheel is prevented by means of the awl 41 which is secured at one end of the inturned portion 42 of the supporting member 5 by means of the screw 43, the other end of the pawl 41 being held in engagement with the ratchet teeth by its own resiliency.

Insulatedly secured to the supporting member 6 in any desired manner, are a pair of contact springs 44 and 45, one of which is slightly longer than the other. These contact springs are-adapted to engage the seg-' ments 28 in the operation of the switch for a purpose which will hereinafter appear. The contact sprin' 46 is also-insulatedly secured to the mem er 6 and is arranged to' engage the segments 28. I a,

Referring to Fi 4, we Wlll now describe the manner in which the switch operates in connecting a calling subscribersline to one of the trunks terminating on the terminal rod 4. It will be noted that 33 of the rods 4 are indicated in Fig. 4. These represent the terminals of a group of ten trunks, and are divided into three groups of I eleven rods each. The first terminal rod in each group is an extra contact, and when not in use the switch always rests with three of its five brushes on. the rods as shown in Figs. 2 and 4. The lowermost group of rods are the sleeve or test terminals of the trunks, and the upper two groups are the terminals of the tip and ring or talking conductors of the trunk. Of course, it is to be understood that the correspondingly positioned rods in each of the three groups are terminals of the same trunk. Five brushes 28 are shown on the switch, but only three of these are employed at a time, one of the brushes passing into engagement with the first contact rod of the lower group at the instant that another of said brushes passes from engagement with the last rod of the upper group. The first rod of the test terminal group is permanently'connected to the battery through a resistance 40. e

We will now assume that the subscriber at station A initiates a call by removing the receiver from its hook. A circuit will be completed from the battery through the resistance 40, brush 29 in engagement therewith, conducting segment 28' to which said brush is secured, the fixed wiper 34, through the windings of relay 50 in series, outer left armature and back contact of said relay, over the lower side of the subscribers line, through the substation thereof, back over the upper side of the line, to ground through the outermost right armature and back contact of relay 50. Relay 50 is energized and' attracts its, armature completing a circuit from battery through interrupter 51, the innermost right armature and front contact of relay 50, contact spring 46 and the conductive segment 28 engaged thereby, contact spring 45 and the winding of thev stepping magnet 36 to, ground. Magnet 36 will at-- tract its armature, causing the switch to rotate an amount equal to the distance between two successive terminal rods. It may be here noted that whenever the switch is notin use it will be so positioned that the contact springs 45 and 46 will engage one of the segments 28 near the opposite ends thereof, and contact spring 44 will engage the insulating disk 25 between the segments 28. The first step of the switch will serve to move the next segment 28 into engagement with spring 44 and 45.

When relay 50 attracted its innermost left armature, it closed a locking circuit for it self from battery through resistance 40,

brush 29, segment 28, wiper 34 and left winding ofsaid relay to ground. In taking the first step, the lower switch brush 29 is moved from engagement with the first terminal rod and into engagement with the test terminal of the firstv trunk in the group. The test terminals of idle trunks will be connected to battery in a manner which will be presently described.

Now, when the lower brush 29 moves from engagement with the normal or first rod, this locking circuit will be broken and relay 50 will retract its armatures. However, if the first trunk is idle, lower brush 29 will again be supplied with battery and a circuit corresponding to that first traced through the windings of relay 50 will be again established, causin said relay to again attract its armature and again lock up through its innermost left armature. As the springs 45 and 46 are not now electrically connected, spring 45 being now in engagement with the next segment 28, the circuit for stepping magnet will be broken and the switc will sto Essuming, however, that the first two trunks in the group are busy, the test contacts thereof will be connected to ground by a circuit extending from the brush 29 of the switch which previously engaged the test rod of the busy trunks, thence through the conducting segment 28 -and wiper 34 of said switch to ground, through the left winding and innermost left armature of the relay 5( of the line to which the engaged switch is individual. ance shunt around the series windings of the relay 50 and prevents this relay from becoming energized-again when the brush 29 engages the test contact of the first trunk, and this relay will remain de'nergized until the test brush 29 engages the test terminal of an idle trunk. A circuit will now extend from battery. through the interrupter 51, the innermost'right armature and back contact of relay 50, contact spring 44, segment 28, contact spring 45 and the winding of stepping magnet 36 to ground. .Magnet 36 will be energized and deenergized by the operation of the interrupter 51, causing the brushes 29 to move from terminal to terminal of the group of trunks. When the brush traversing the lower group of terminal rods engages the contact of an idle trunk which in the present disclosure is the fourth rod, a circuit will be completed from battery through resistance 52, 011 normal contact 53 of the selector switch to which said trunk extends, the fourth of the lower group of terminal rods, brush 29, segment 28, wiper 34, the windings of relay 50 in series, 11 permost left armature and back contact 0 said relay, over the lower side of the subscribers line, and back over the upper side of the line to ground through the outermost right armature and' back contact of relay 50. Relay 50 will be energized and locked up through its left winding as previously described. The current flowing through interrupter 51 will now be without efiect on the stepping magnet 36, as the contact spring 45 is no longer in engagement with the same segment 28 as spring 46.

Upon the attraction of the armatures of relay 50, a circuit was closed from battery through the right winding'of stepping relay This circuitplaces a low resist IHPUOIIS 1n the circuit 0 upon its hook.

- ture.

54 of the selector switch to the fourth terminal rod of the upper group, brush 29, segment 28, wiper 32, front contact and outermost left armature of relay 50, over the subscribers line, through the substation, back over the other side of the line, outermost right armature and front contact of relay 50, w1per 33, segment 28, brush 29 connected thereto, to the fourth terminal rod in the middle group and thence back to battery through the left winding of relay 54. Relay 54 will attract its armature, causing the energization of the slow-to-release relay 55. Relay 55 at its left armature will connect battery through resistance 52 to the test terminal rod of the selected trunk. As this relay is slow to release it will not retract its armature during the brief interruptions in its circuit, due to the operation of the subscribers sending device, thus insuring that busy potential will be supplied to the test terminal of the trunk when the ofi-normal contact 53 is open.

The subscriber at station A now operates his sending device, causm a series of interrelay 54. With each interruption relay 54 retracts its armature, completing a circuit from battery through the stepping magnet 56, side switch wiper 57, slow-to-release relay 58, front contact and right armature of relay 55 to ground through the back contact and armature of relay 54. By the repeated energiza tion of the magnet 56 due to the vibration of the armature of relay 54 the selector switch brushes 60. and 61 will be stepped around in the usual manner. Therelay 58 may be used to control the operation of a side switch magnet in a manner which is well understood. It is believed that further description of the manner in which the first selector switch and the succeeding switches are operated is unnecessary.

ssuming now that a connection has been established from the calling subscriber at station A to another subscriber, that the conversation has been completed and the subscriber at station A replaces his receiver This will open the circuit for relay 54, causing it to retract its arma- The circuit of relay 55 being now permanently open, it will also retract its armature. This opens the lead from the test terminal of the trunk, to battery through resistance 52, thus interrupting the locking circuit through the left winding of relay 50, which When relay 50 retracted its armatures, a circuit was completed from battery through interrupter 51, contact spring 44, segment 28, spring 45 and the winding of stepping magnet 36 to ground. Magnet 36 is repeatedly energized and denergized by the action of the interrupter 51 until brush 44 passes oil from segment 28 and on to the insulating strip between this segment and the next segment 28. The circuit for magnet 36 being now broken, the switch will come to rest with three of its brushes 29 again positioned at the .first terminal rods of the groups respectively, that is in a position similar to that from which it was moved upon the initiation of the call.

The line switch arrangement and the circuits therefor provided by the present invention are exceedingly simple and cheap in construction. By the parallel rod type of multiple terminal bank, the cost of the multiple contacts for the trunks is made very low. These terminal wires are also readily replaced if they become worn or bent, and are at all times readily visible so that any defect may be readily noted. The movable elements of the switches are also so arranged that one may be readily removed and another one substituted.

The operating circuits for the switch are of such a character that a single'relay is employed to control the operation of the stepping magnet. This relay is operated first to start the switch. It then becomes denergized, and is operated again to stop the switch; that is, it acts as a test relay. At the end of the conversation it is actuated a third time to cause the release or return to normal of the switch. Thus, this single relay has a three-fold function-being a line rela a test relay and a release relay.

T e selector switch circuits shown within the rectangle at the lower right corner of Fig. 4 form no part of the present invention, but have been included in the present disclosure in order to make it evident in what manner the busy potential is supplied to the test terminals of the trunks, and also the manner in which the release of the line-1 while the switch is in action, the only change necessary in the circuits being the missions of the interrupter 51.

What is claimed is:

1. In a telephone system, a subscribers line, a line relay, a group of trunk line terminal contacts, an automatic switch hav ng movable contacts, a power magnet for causv ing said movable contacts to move over said terminal contacts, a single winding on sald power magnet, an interrupter, circuits for said winding extending through front and back contacts of said line relay to said interrupter, an energizing circuit for said relay individual thereto, means for completing said energizing circuit, when the subscriber initiates a call to close a circuit of the winding on said power magnet at the front contact of said relay to cause the initial movement of said switch, a circuit for said winding closed at the back contact of said relay to continue the movement of said switch, and means for again energizing said relay to stop said switch when the contact of an idle trunk is found.

2. In a telephone system, a switch, a motor magnet for said switch, a single winding for said magnet, a relay, an interrupter, an energizing circuit for said relay. individual thereto, means for completing said energizing circuit, an energizing circuit for the winding of said magnet closed through an armature and front contact of said relay and said interrupter to cause the initial movement of said switch, a circuit for the winding of said magnet closed through the armature and back contact of said relay and said interrupter to continue the movement of said switch, and means for energizing said relay to stop said switch.

3. In a telephone system, an incoming line, a switch having brushes at which said line terminates, outgoing lines having terminals arranged to be engaged by said brushes, a relay, an energizing circuit for said relay individual thereto, means for completing said energizing circuit upon the initiation of a call on said line, a motor, magnet for said switch, a single winding on said motor magnet, an interrupter, a circuit including said winding and interrupter closed at a front contact of said relay to cause the initial movement of said switch, means for thereupon deenergizing said relay, a circuit including said winding and interrupter closed through a back contact of said relay to continue the movement of said switch, and means for energizing said relay to stop said switch when the terminals of an idle outgoing line are engaged.

4. In a telephone system, an incoming line, a switch having brushes at which said line terminates, outgoing lines having terminals arranged to be engaged by said brushes, a relay, an energizing circuit for said relay individual thereto, means for completing said energizing circuit upon the initiation of a call on said line, a motor magnet for said switch, an interrupter, a circuit foizsaid winding and interrupter closed at a front contact of said relay to cause the initial movement of said switch, said circuit including contacts which are closed only in a normal position of theswitch, means for thereupon deenergizing said relay, a circuit for said winding and interrupter closed through said armature and back contact of said relay to continue the movement of said switch, said last-mentioned circuit including contacts which are closed only while said switch is in an off-normal position, means for energizing said relay to stop said switch when the terminals of an idle outgoing line are engaged, means for again deenergizing said relay to again establish the last-mentioned circuit for the winding of said magnet to return said switch to a normal position.

5. In a telephone system, a 'subscribers line, a switch having brushes at which said line terminates, outgoing lines having terminals arranged to be engaged .by said brushes, a relay, an energizing circuit for said relay individual thereto, means for completing said energizing circuit in series with both sides of the subscribers line upon the initiation of a call on said line, a motor magnet for said switch, a single winding on said magnet, an interrupter, a circuit for said winding and interrupter in series closed at a front contact of said relay, a circuitfor said winding and interrupter in series closed through a back contact of said relay to continue the movement of said switch, and means for energizing said relay to stop said switch when the terminals of an idle outoin line are engaged. g 6. iin a telephone system, a subscribers line, a switch having brushes at which said line terminates, outgoing lines having terminals arranged to be engaged by said brushes, a relay, an energizing circuit for said relay individual thereto, means for completing said energizing circuit in series with both sides of a subscribers line upon the initiation of a call on said line, a motor magnet for said switch, a single winding on said magnet, an interrupter, a circuit for said winding and interrupter in series closed at a front contact of said relay to cause the initial movement of said switch, said circuit including contacts which are closed only in a normal position of the switch, means for thereupon deenergizing said relay, a circuit for said winding and interrupter in series closed through the armature and back contact of said relay to continue the movement of said switch, said last-mentioned circuit including contacts which are closed only while said switch is in an oii-normd position, means for energizing said relay to stop said switch when the terminals of an idle outgoing line are engaged, and means for again deenergizing said relay to again establish the last-mentioned circuit for said winding to return said switch to a normal position.

In witness whereof, we hereunto subscribe our names the 24th and 27th days of January A. D., 1916, respectively.

ARTHUR H. ADAMS. ALBEN E. 

